Silencing lncRNA TUG1 inhibits osteo/odontogenic differentiation of human dental pulp stem cells through the Wnt/β-catenin signaling pathway

Abstract

Background Human dental pulp stem cells (hDPSCs), a type of mesenchymal stem cells (MSCs), can be induced to various tissues under appropriate conditions. LncRNA TUG1 has been shown to exert promoting effect on osteogenic differentiation, while its role in osteo/odontogenic differentiation of hDPSCs remains unclear. This study aimed to investigate the role of TUG1 during osteo/odontogenic differentiation of hDPSCs. Materials and methods The hDPSCs were characterized and identified using flow cytometry and assessment of their multidirectional differentiation capabilities. TUG1 knockdown was achieved by lentivirus-mediated TUG1 short hairpin RNA (shRNA) and confirmed by qRT-PCR. The osteo/odontogenic ability was evaluated by alkaline phosphatase (ALP) staining, alizarin red S (ARS) staining, qRT-PCR, and western blot. Lithium chloride (LiCl) was used as an agonist of the Wnt/β-catenin signaling pathway. Results The hDPSCs were characterized by flow cytometry and multidirectional differentiation experiments successfully. The expression of TUG1 was upregulated during the process of the osteo/odontogenic differentiation of hDPSCs. Knockdown of TUG1 attenuated the osteo/odontogenic potential of hDPSCs and decreased the expression of DSPP, DMP-1, Runx2, OCN and OPN. Besides, silencing of TUG1 significantly reduced the levels of the Wnt/β-catenin pathway related marker proteins, Wnt3a and β-catenin, while activation of Wnt/β-catenin signaling by LiCl markedly reversed the inhibitory effect of TUG1 silencing on the osteo/odontogenic differentiation of hDPSCs. Conclusion Our results imply that TUG1 might function through the Wnt/β-catenin signaling pathway to promote the osteo/odontogenic differentiation of hDPSCs.